Polyhedral Oligomeric SilSesquioxanes (“POSS”) are cage-structures having a silicon-oxide (SiO1.5) core surrounded by aliphatic or aromatic organic functionality. One such POSS derivative, octakis(1H,1H,2H,2H-heptadecafluorodecyl) POSS (“F-POSS”), possesses a periphery of long-chain fluorinated alkyl groups and has been determined to possess the lowest surface energy value of any crystalline solid (γsv=9.3 mN/m). Superhydrophobic (contact angles of a water droplet exceeding 150°) and oleophobic (repelled by oil) surfaces have been produced by casting F-POSS materials onto a substrate or blending the F-POSS material into a polymer matrix.
Conventionally, F-POSS has been used as standalone compounds without further reactive chemical functionality; however, this absence of reactive chemical functionality limits solubility in common solvents, the mechanical robustness, and abrasion resistance of surfaces comprising these materials. One attempt to overcome such limitations has been an incompletely-condensed F-POSS compound with silanol functionality, which enabled new, robust, low surface energy hybrid materials. In fact, incompletely-condensed silsesquioxane frameworks have emerged with alkyl and/or aryl peripheries and are operable as synthons for creating hybrid inorganic-organic materials, as models for silica, for catalyst support, and as precursors for other silsesquioxane containing polymers.
Unfortunately, none of the conventional synthesis strategies are viable to produce long-chain (more than three carbon atoms) F-POSS compounds possessing additional reactive or non-reactive functionality beyond alkyl or aryl peripheries. Exemplary strategies, such as those described in U.S. Pat. No. 7,053,167, entitled SILSESQUIOXANE DERIVATIVE HAVING FUNCTIONAL GROUP, issued to Ito et al. on Apr. 8, 2004 and U.S. Pat. No. 7,291,747, entitled NOVEL SILICON COMPOUNDS AND PROCESS FOR PREPARATION THEREOF, issued to Oikawa et al. on Nov. 6, 2007 (disclosures incorporated herein by reference, in their entireties), have not produced long-chain F-POSS-(ONa)3 having more than three carbon atoms. Modified methods have produced (3,3,3-trifluoropropyl)7Si7O9(ONa)3, which can be derivatized with long-chain fluorinated trichlorosilanes to produce low surface energy materials, but the trifluoropropyl groups are still limited in chain length.
While these conventional methods have proven successful for the synthesis of incompletely-condensed compounds possessing alkyl- and aryl-functionality, there remains a need for a method of synthesizing an incompletely-condensed, long-chain F-POSS compound.